Center text on painter

[masoroso]

Hi All,

How can I center text at a given x position on a painter?

I use a function to draw lines and above the line I want to set the value of the line (like 0, 2, 4, 6 etc) How can I center these values? I now use something like p.drawText(x,y,`bla') but there must be a way to find out how large 'bla' will be in pixels?

Thanks in advance
Rob

[munna]

Use QFontMetrics to find the height, width, ascent and descent of the text you use.

[jacek]

I now use something like p.drawText(x,y,`bla') but there must be a way to find out how large 'bla' will be in pixels?

Either use QPainter::boundingRect() or paint the text using different QPainter::drawText() method (the one which takes QRect as the first parameter).

[masoroso]

thanks!

I now use

QFontMetrics fm(painter.font());
...
tw = fm.width(sx);
painter.drawText(x+tw/2, y, sx);

QFontMetrics fm(painter.font());
...
tw = fm.width(sx);
painter.drawText(x+tw/2, y, sx);

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btw. I did not understand the boundingRect option... I still need to know the rect dimensions before I call `boundingrect'??

Anyway, it works this way so thank you both,
Rob

[masoroso]

whoops sorry..

boundingrect is a better option in this case because QFontMetrics does not have a height() option (and I also need to align to the center of the height).

The code is now rewritten to

QFontMetrics fm(painter.font());
..
xoffset = fm.boundingRect(sx).width()/2;
painter.drawText(x - xoffset, y, sx);

QFontMetrics fm(painter.font());
..
xoffset = fm.boundingRect(sx).width()/2;
painter.drawText(x - xoffset, y, sx);

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[jacek]

I still need to know the rect dimensions before I call `boundingrect'??

No, you don't have to:

If the text does not fit within the given rectangle using the specified flags, the function returns the required rectangle.